Question

Recall that profit equals revenue minus cost. For the revenue and cost functions​ shown, answer parts ​(a) through​ (e) below.

R(x)=440x-2x^2 and c=200x+6120

a) what is break even point?
I am stuck in figuring out how the solution is
-60 6√15 When I do the quadratic function?

Answer 1

i know that 120/ 2= 60

but the 6 √15 is where i am confused at.

Answer 2

the whole quadratic function is
120 √120^2-4(1)(3060) divide by 2

Answer 3

please help

Answer 4

do u need more info??

Answer 5

r-c gives
-2x^2 +440x - 200x -6120 or factoring out -2
-2(x^2 - 120x + 3060) = 0

i think this is what you got??

Answer 6

dividing both sides by -2 gives
x^2 - 120x + 3060 = 0

are we ok so far??

Answer 7

yeah

Answer 8

when we do the quadratic function, im stuck at figuring out why the answer is

60 6√15

Answer 9

we can put in a calculator
http://www.math.com/students/calculators/source/quadratic.htm

or use the quadratic formula

i used complete the square
x^2 - 120x + 3060 =0 subtracting 3060 to both sides gives
x^2 - 120x =-3060 and then add 120/2 and square it gives
x^2 - 120x + 3600 =-3060 + 3600
(x-60)^2 = 540

Answer 10

sqrt bth sides
x-60 = + or - sqrt 540

Answer 11

540 = 36*15

Answer 12

doyou see it now maria??

Answer 13

im looking at the way its done over here,

i will attach it

Answer 14

sqrt540 = sqrt6*6*15 so sqrt=
6sqrt 15

Answer 15

im trying to do an online assignment and it showing me to do it this way

Answer 16

im just trying to figure out the 6/15 part

Answer 17

sqrt 2160 =sqrt(144*15) = 12sqrt15 divided by the 2 gives 6sqrt15

Answer 18

same as what i got completing the square

Answer 19

can you see it now??

Answer 20

how u get 144? you jst have to figure out what multiplies to 2160?

Answer 21

yes

Answer 22

cause i was doing 2160square root equals 46.48

Answer 23

I get it now just how you know which factor to use??

Answer 24

just try squares 4 9 16 ... so on

Answer 25

ohh sorry it been a while since I learned this stuff

Answer 26

thanks for your help

Answer 27

no problem.